HuxactuieJlid Sponge from S>uf/i Africa. 4.j9 



2. Oxyhexasters, 90-100 /i in dianieter, witli usually bi- 

 furcate, but occaaionally siiii^lo, roiiLjIiened rays. 



Of the two specimens, the smaller, wliicli is almost globular, 

 has only a slightly developed r()ot-tuft ; the larger has several 

 long digitate processes about 9 centim. long by 1 centiin. 

 thick, provided with tufts of long j)entact basalia, forming a 

 dense root-tuft. The total length of the large specimen is 

 23 centim., tiie breadth at the base 18 centim., length of 

 body 13 centim., of root-tuft 10 centim. ; diameter of orifice 

 7x6 centim.; depth of gastral cavity about 6 centim. It 

 should be remarked that the specimens have probably been 

 considerably distorted by compression, as the outer veil is 

 only intact over a small area of the smaller specimen. 



i'lie dimensions of the smaller specimen are : — Length 

 13 centim., with three digitate processes 2*5 centim. in lengtli ; 

 breadth 13 centim. ; orifice 4 centim. ; depth of gastral cavity 

 about 4 centim. 



Diact basalia are apparently absent, though very numerous 

 long spicules occur which are broken at the end. All the 

 young complete spicules are pentiictine, and I have been 

 unable to find among them any diacts. In addition to the 

 shape of the sponge and the fissile character of the principal 

 rays of the discoctasters, the occurrence of spined diacts in the 

 gastral membrane characterizes the new species; in all of 

 the eight previously described species, [3] p. 10>, of this 

 genus the aulogastralia are hexactine or hexactine and pent- 

 actine. In a species of a closely allied genus, Stauroca/j/ptus 

 pleorhnphideSf Ijinia, [4] p. 58, both the dermal and gastral 

 membranes are supported by spinous diactines. 



Locality. Large specimen, 73 miles north and 28 miles e.ist 

 of Lion's Head, 140 fatli., Cape Colony : small specimen, 

 63 miles north and 34 miles east of Lion's Head, 154 tath. 

 Both specimens obtained by shrimp-trawl. 



[1] ScnuLZK, F. E. " Revitiion des Systems der Asconematiden und 



Ko-ssellideu," Sit2ungsb. Akud. ^^'l8S. Berlin, 1897. 



[2] . ' Cliallenjer ' lie.vactinellida, 1887, p. loo. 



[3] . ' Aiueiikiiuiscbe He.xactinelliden uach dem Materiale der 



Albatross-Expeditiou,' 1899. 

 [4] Ijima, I. " Kevision of Ilexactinellids with Discoctasters, with 



JJescriptions of Five new Species,"' Annotatioues zoologicw 



JaponeDsea, 1897, vol. i. 



EXPLANATION OF PLATE VIII. 



Fig. 1. Rhah(foc(ih/pfiis liphodigitatns, sp. n., large specimen, reduced to 

 fine third natural size. The fipiire has been .sJiLjlitly idealized, 

 in order to show the gastral oritice, the basal digit it^ procejses, 



o2* 



